The II was partially built of wood due to the
shortage of metal
alloys.

The Ki-84 Hayate (Gale), known to the
Allies as
"Frank", was probably the best Japanese
fighter to enter production. However, by the time "Frank" went
into production,
quality control was so poor that the aircraft coming out of the
factory
were
barely serviceable. In particular, there was a tendency for
the landing gear,
which were poorly heat-treated, to fold up. There were also
persistent
problems with the fuel injection system. But those that
worked and were
piloted well could
sometimes
outfly a Mustang.

The design dated to early 1942, when the Army
called for a new fighter to replace the Ki-43
"Oscar". This was a matter of foresightedness rather than
any
disappointment with "Oscar". The new fighter was to have a long
range,
high speed, and improved armament and armor
protection. The design team, led by Koyama T., completed a
prototype by
March 1943 and this proved to have unusually few bugs. Service
trials
production began in August 1943 and quantity production began in
April
1944.

Unlike most Japanese fighters, "Frank" was
properly armed and protected. The basic "Zero" pattern of cannon in
the
wings and machine guns in the nose cowling was retained in the Ia,
but
the cannon were higher velocity with a much larger ammunition
loadout
and the machine guns were heavy rather than rifle caliber. The Ib
and
Ic had
powerful all-cannon armament.

The first operational use of "Frank" was with 22 Air Brigade in China in March
1944, where
it operated against Chennault's14 Air
Force.
The new fighter must have come as something of a rude
shock to the American
flyers, given the satisfaction with which the Japanese regarded
the
performance of the experimental unit. "Frank" subsequently flew in
the Philippines,
at Okinawa, and in the final
defense
of Japan. So great was the Japanese faith in the design that, at
the
time of the surrender,
underground factories were being built to produce "Frank" at the
rate
of 200 per month.

The American command
took the threat posed by "Frank" seriously enough to designate the
Ota assembly plant as a priority target for strategic bombing on
11 November 1944.